One of the primary goals of clinical health research is to develop compositions and methods that rapidly and selectively direct cells of the immune system to achieve therapeutic objectives. For example, vaccines are used to prime the immune system to target antigens associated with unwanted cells. The biological processes underlying conventional vaccines, however, can render them ineffective against many unwanted cells based on, among other factors, the time it takes to prime the immune system, the amount or degree to which the natural immune system can be primed against certain unwanted cell types and over time, the depletion of immune system resources. As examples, conventional vaccine approaches can be ineffective against cancer cells and cells affected by certain infectious diseases.
Using cancer cells as an example of an unwanted cell type, vaccines can be capable of targeting the immune system to destroy cancer cells in some patients. The immune response using this approach, however, requires months to mature and during this time, cancers can significantly progress and become fatal. Thus, conventional vaccines do not provide an adequate method to target and destroy unwanted cancer cells.
To achieve more rapid and potent cancer cell destruction, infusions of autologous T cells genetically targeted to tumor antigen are currently being tested in the clinic and represent a promising treatment option. However, T-cell transfer therapies are also time and labor-intense and must be personalized for each patient in cell production facilities, which are available only at a few highly specialized cancer centers worldwide. Similar issues are encountered with a number of other unwanted cell types. Thus, additional solutions are needed that allow rapid and selective direction of cells of the immune system to achieve therapeutic objectives